Buggy code:
public class JdbcDBClient extends DB implements JdbcDBClientConstants { private ArrayList < Connection > conns ; private boolean initialized = false ; private Properties props ; private Integer jdbcFetchSize ; private static final String DEFAULT_PROP = "" ; private ConcurrentMap < JdbcDBClient . StatementType , PreparedStatement > cachedStatements ; private int numFields ; private static class StatementType { enum Type { INSERT ( 1 ) , DELETE ( 2 ) , READ ( 3 ) , UPDATE ( 4 ) , SCAN ( 5 ) ; int internalType ; private Type ( int type ) { } int getHashCode ( ) { } } JdbcDBClient . StatementType . Type type ; int shardIndex ; int numFields ; String tableName ; StatementType ( JdbcDBClient . StatementType . Type type , String tableName , int numFields , int _shardIndex ) { } @ Override public int hashCode ( ) { } @ Override public boolean equals ( Object obj ) { } } private int getShardIndexByKey ( String key ) { } private Connection getShardConnectionByKey ( String key ) { } private void cleanupAllConnections ( ) throws SQLException { } @ Override public void init ( ) throws DBException { } @ Override public void cleanup ( ) throws DBException { } private PreparedStatement createAndCacheInsertStatement ( JdbcDBClient . StatementType insertType , String key ) throws SQLException { } private PreparedStatement createAndCacheReadStatement ( JdbcDBClient . StatementType readType , String key ) throws SQLException { } private PreparedStatement createAndCacheDeleteStatement ( JdbcDBClient . StatementType deleteType , String key ) throws SQLException { } private PreparedStatement createAndCacheUpdateStatement ( JdbcDBClient . StatementType updateType , String key ) throws SQLException { } private PreparedStatement createAndCacheScanStatement ( JdbcDBClient . StatementType scanType , String key ) throws SQLException { } @ Override public int readOne ( String table , String key , String field , Map < String , ByteIterator > result ) { } @ Override public int readAll ( String table , String key , Map < String , ByteIterator > result ) { } public int read ( String tableName , String key , Set < String > fields , Map < String , ByteIterator > result ) { } @ Override public int scanOne ( String table , String startkey , int recordcount , String field , List < Map < String , ByteIterator > > result ) { } @ Override public int scanAll ( String table , String startkey , int recordcount , List < Map < String , ByteIterator > > result ) { } public int scan ( String tableName , String startKey , int recordcount , Set < String > fields , List < Map < String , ByteIterator > > result ) { } @ Override public int updateOne ( String table , String key , String field , ByteIterator value ) { } @ Override public int updateAll ( String table , String key , Map < String , ByteIterator > values ) { } public int update ( String tableName , String key , Map < String , ByteIterator > values ) { } @ Override public int insert ( String tableName , String key , Map < String , ByteIterator > values ) { if ( tableName == null ) { return - 1 ; } if ( key == null ) { return - 1 ; } try { JdbcDBClient . StatementType type = new JdbcDBClient . StatementType ( JdbcDBClient . StatementType . Type . INSERT , tableName , numFields , getShardIndexByKey ( key ) ) ; PreparedStatement insertStatement = cachedStatements . get ( type ) ; if ( insertStatement == null ) { insertStatement = createAndCacheInsertStatement ( type , key ) ; } insertStatement . setString ( 1 , key ) ; int index = 2 ; for ( Map . Entry < String , ByteIterator > entry : values . entrySet ( ) ) { byte [ ] bytes = entry . getValue ( ) . toArray ( ) ; insertStatement . setBytes ( ( index ++ ) , bytes ) ; } <START_BUG> while ( index < ( ( numFields ) + 1 ) ) { <END_BUG> insertStatement . setBytes ( ( index ++ ) , null ) ; } int result = insertStatement . executeUpdate ( ) ; if ( result == 1 ) return SUCCESS ; else return 1 ; } catch ( SQLException e ) { System . err . println ( ( ( "Error<seq2seq4repair_space>in<seq2seq4repair_space>processing<seq2seq4repair_space>insert<seq2seq4repair_space>to<seq2seq4repair_space>table:<seq2seq4repair_space>" + tableName ) + e ) ) ; return - 1 ; } } @ Override public int delete ( String tableName , String key ) { } }

Fix:
while ( index < ( ( numFields ) + 2 ) ) {